They’re just “flavours” but they can guide you if you are not sure about the way to go. For me I gathered all the monsters I wanted, plus the modifiers, and that got me a game. If they were real requirements, I’d say I didn’t hit them all hard enough. Like, players share candy, but that’s not really something precious. And I called the end of the game “sunrise”, did a garish colours version, but that’s kind of Halloweenwashing.
In the end, the costume thing did stick. So I’d say it’s more like throwing onigiris to the wall and see what sticks.
In the land of creativity, you do what you do, and that’s OK.